1. Field of the Invention
The present invention relates to ultrasound imaging, and more particularly, to robotic 5-dimensional (5D) ultrasound imaging.
2. Discussion of the Related Art
Ultrasound is widely used in the medical community for intervention therapy. Examples include thermal ablation, external beam radiation therapy (EBRT), Brachy therapy, and needle insertion procedures, including biopsy procedures.
As stated, thermal ablation is but one procedure for which ultrasound is commonly used. Primary and metastatic liver cancer represents a significant source of morbidity and mortality in the United States, as well as worldwide. The medical community has focused on such techniques as thermal ablation, and in particular, radiofrequency ablation (RFA), to treat this and other similar diseases. Thermal ablation typically utilizes images to guide the placement of the ablation probe to or within the target area (e.g., a lesion or tumor) of the liver parenchyma. Heat created around the electrode, which is generally located at the tip of the ablation probe, is conducted into the target area tissue, causing coagulative necrosis at a temperature between 50° C. and 100° C.
There are several problems associated with conventional thermal ablation techniques. First and foremost is the ability to effectively utilize the imagery to precisely control the ablation probe during the ablation procedure. To some extent, this problem has been addressed by the development and use of 3D ultrasound imaging systems. While ultrasound is commonly used for target imaging, in general, and ablation monitoring, problems still exist even with these systems, as they do not provide adequate imagery and, as a result, they cannot effectively identify, segment, monitor or track target tissue, nor do they facilitate planning or control prior to and during the ablation process.
One reason conventional robotic 3D ultrasound systems are inadequate is that ultrasound cannot detect all lesions and tumors. Lesions and tumors are may be categorized as either hyperechoic (i.e., appear brighter than the surrounding tissue in an image), hypoechoic (i.e., appear darker than the surrounding tissue in an image), or isoechoic (i.e., have the same intensity as the surrounding tissue in an image). Ultrasound cannot visualize lesions or tumors that are isoechoic. Thus, conventional 3D ultrasound systems cannot effectively identify, segment, monitor or track target tissue, or facilitate planning and control prior to and during an ablation process where the target tissue is isoechoic.
Another reason conventional 3D ultrasound based systems are not always effective is that such systems do not necessarily provide adequate imaging in a noisy environment. As one skilled in the art will appreciate, the operation of an ablation probe generates a significant amount of noise which otherwise interferes with the ultrasound signal, and the ability of the system to generate accurate imagery.
Thermal ablation is, as stated, only one example of a medical procedure for which ultrasound is used to facilitate the procedure. Given the important of ablation therapy, as well as other medical procedures that utilize ultrasound, it is clear there is a tremendous need to enhance the capabilities of imaging systems to overcome the problems described above.